• mandrill;
  • ecology;
  • seed dispersal;
  • competition


An ecological study of the mandrill was conducted in northeastern and central Gabon from November 1982 to October 1983. The purpose of the study was to gather basic ecological data on the mandrill as a foundation for a future long-term study of this species. Data were collected by direct observation, by collecting evidence left along fresh trails, and by fecal and stomach content analyses. Fruits constituted the mandrill's major dietary item, supplemented by various plant parts and numerous insect species. Small vertebrates were also occasionally consumed. Mandrills fed primarily on the forest floor but also climbed trees to obtain food, probably on a more frequent basis than do the Papio species. The majority of mandrill sightings and identified foods were attributed to primary forest, but foraging also occurred in secondary, riparian, and inundated forests. The patchy distribution and seasonal fluctuation of fruiting trees in the rainforests of Gabon may influence mandrill home range usage. The electric feeding behavior and large home ranges estimated for mandrill groups suggest that this species may play an important role in seed dispersal. Interspecific competition for food sources may be mitigated by species' preferences for different fruit parts. The mandrill is able to utilize foods in both arboreal and terrestrial ecological niches.